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comm.MuellerMullerTimingSynchronizer System object

Package: comm

Recover symbol timing phase using Mueller-Muller method

comm.MuellerMullerTimingSynchronizer will be removed in a future release. Use comm.SymbolSynchronizer instead.


The MuellerMullerTimingSynchronizer object recovers the symbol timing phase of the input signal using the Mueller-Muller method. This object implements a decision-directed, data-aided feedback method that requires prior recovery of the carrier phase.

To recover the symbol timing phase of the input signal:

  1. Define and set up your Mueller-Muller timing synchronizer object. See Construction.

  2. Call step to recover the symbol timing phase of the input signal according to the properties of comm.MuellerMullerTimingSynchronizer. The behavior of step is specific to each object in the toolbox.

    Note:   Starting in R2016b, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.


H = comm.MuellerMullerTimingSynchronizer creates a timing synchronizer System object, H. This object recovers the symbol timing phase of the input signal using the Mueller-Muller method.

H = comm.MuellerMullerTimingSynchronizer(Name,Value) creates a Mueller-Muller timing recovery object, H, with each specified property set to the specified value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).



Number of samples representing each symbol

Specify the number of samples that represent each symbol in the input signal as an integer-valued scalar greater than 1. The default is 4.


Error update step size

Specify the step size for updating successive timing phase estimates as a positive real scalar value. The default is 0.05. Typically, this number is less than 1/SamplesPerSymbol, which corresponds to a slowly varying timing phase. This property is tunable.


Enable synchronization reset input

Set this property to true to enable resetting the timing phase recovery process based on an input argument value. The default is false. When you set this property to true, you must specify a reset input value to the step method. When the reset input is a nonzero value, the object restarts the timing phase recovery process. When you set this property to false, the object does not restart.


Condition for timing phase recovery reset

Specify the conditions to reset the timing phase recovery process as Never | Every frame. The default is Never. When you set this property to Never, the phase recovery process never restarts. The object operates continuously, retaining information from one symbol to the next. When you set this property to Every frame, the timing phase recovery restarts at the start of each frame of data. Thus, restart occurs each time the object calls the step method. This property applies when you set the ResetInputPort property to false.


resetReset states of Mueller-Muller timing phase synchronizer
stepRecover symbol timing phase using Mueller-Muller method
Common to All System Objects

Create System object with same property values


Expected number of inputs to a System object


Expected number of outputs of a System object


Check locked states of a System object (logical)


Allow System object property value changes


Recover timing phase using the Mueller-Muller method.

% Initialize some data 
    L = 16; M = 2; numSymb = 100; snrdB = 30;
    R = 25; rollOff = 0.75; filtDelay = 3; g = 0.07; delay = 6.6498;

% Create System objects
    hMod = comm.DPSKModulator(M, 'PhaseRotation', 0);
    hTxFilter = comm.RaisedCosineTransmitFilter(...
        'RolloffFactor', rollOff, ...
        'FilterSpanInSymbols', 2*filtDelay, ...
        'OutputSamplesPerSymbol', L);
    hDelay = dsp.VariableFractionalDelay('MaximumDelay', L);
    hChan = comm.AWGNChannel(...
        'NoiseMethod', 'Signal to noise ratio (SNR)', ...
        'SNR', snrdB, 'SignalPower', 1/L);
    hRxFilter = comm.RaisedCosineReceiveFilter(...
        'RolloffFactor', rollOff, ...
        'FilterSpanInSymbols', 2*filtDelay, ...
        'InputSamplesPerSymbol', L, ...
        'DecimationFactor', 1);
    hSync = comm.MuellerMullerTimingSynchronizer('SamplesPerSymbol', L, ...
         'ErrorUpdateGain', g);

% Generate random data
    data = randi([0 M-1], numSymb, 1);

% Modulate and filter transmitter data
    modData = step(hMod, data);
    filterData = step(hTxFilter, modData);

% Introduce a random delay
    delayedData = step(hDelay, filterData, delay);

% Add noise
    chData = step(hChan, delayedData);

% Filter the receiver data
    rxData = step(hRxFilter, chData);

% Estimate the delay from the received signal
    [~, phase] = step(hSync, rxData);
    fprintf(1, 'Actual Timing Delay: %f\n', delay);
    fprintf(1, 'Estimated Timing Delay: %f\n', phase(end));


This object implements the algorithm, inputs, and outputs described on the Mueller-Muller Timing Recovery block reference page. The object properties correspond to the block parameters, except:

The Reset parameter corresponds to the ResetInputPort and ResetCondition properties.

Introduced in R2012a

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